Logarithmic, scaled Eddington flux (in units of erg cm^-2 s^-1 Hz^-1) as a function of wavelength/energy, for the supergiant models S30 (black), S40 (green), and S50 (turquoise) with identical mass-loss rates, 10^-8M_⊙/ yr. All models have the same X-ray properties, as denoted in Fig. 5. The Eddington fluxes have been scaled by (R_∗/R_⊙)² and (v_∞/ 1000 km s^-1)² to ensure theoretically similar values of optically thin X-ray emission. The dotted lines denote energies of 350, 150, and 100 eV, corresponding to 35, 83, and 124 Å. (See text.)